Etc.: A sign to make others believe that you know more than you actually do.
I have alway wondered if people knew exactly what they were trying to say when they say et cetra... Most of the time no. It is a very cleverly coined word to give an impression to the listener that the speaker knows what he is talking about but is just too busy too explain them..But in reality it is a word used to cover up his/her ignorance.. okay not always but most of the time..
So the next time you use the word et cetra be sure you know what the et cetra is about coz you may have a listener like me who will prod you on what the etc is about :D